Overwind preventer for timepiece



May 31, 1955 F. MEYER 2,709,332

OVERWIND PREVENTER FOR TIMEPIECE Filed May l5, 1951 2 Sheets-Sheet l \\\mll ll/l////////// Z m I/ a Y R Vl g or.. ll /0/ nl.. TNI... N l/ N l R S WH m Nm f i, lm A ,y .0.. ....W. s /7 n mm n \\u\.. /H/ uw, 5 no "nl \w I 2 1 8 R x Il w 1 ll.\ w f. mi s u 3 s m m. n nl du F l s. .3 Nw Il mf.. ww \S Z 2 n a W /II May 31, 1955 F. MEYER OVERWIND PREVENTER FOR TIMEPIECE 2 Sheets-Sheet 2 Filed May 15' 1951 am mn n N mun WR 4 m mon.. A D E .n.m,vi B

nite States attent OVERWIND PREVENTER FOR TIMEPIECE Friedrich Meyer, Grenchen, Switzerland, assigner to Feiss A. G., Grenchen, Switzerland Application May 15, 195i, Serial No. 226,361 Claims priority, application Switzerland March 14, 1951 2 Ciairds. {CL .5S- 33) My invention relates to timepiece movements and particularly to a movement with an autorr .tic winding mechanism including a lockable oscillating weight.

As is well-known to those skilled in the art in timepiece (watches, clocks etc.) with automatic 'winding mechanisms, provisions must be made to prevent the -2 in temperature, influence the motor spring in such a way that the spring is wound to only halt the desired value so that the timepiece may have a reserve of power ot` only ten to twenty hours.

Also snap mechanisms for positive locking of the oscillating weight have been used, these mechanisms being under the constraint both of the motor spring and of a counterspring, whereby on an excess of the force ot the motor spring beyond the force of the counterspring, a locking member snaps engagement with the oscillating weight. However, these countersprlngs relax with time as they are permanently loaded by the motor spring.

It is an object of my invention to provide a timepiece movement in which the device for locking the oscillating weight is controllable by a diterential gear in operating connection with the barrel and the barrel arbor in such a way that the device stops the oscillating weight after a prescribed winding rotation of the motor spring and releases the weight after a prescribed developing rotation of the motor spring.

Bridles and countersprings are necessary in the movement in accordance with the invention and the winding limit remains the same during the entire lite of the movement and under changes in temperature.

A further object of my invention is to provide a snap mechanism as a locking device to positively engage the oscillating weight.

Another object is to provide a movement in which the dilierential gear bends a spring in both directions of rotation of a drivenmember so that the spring releases a snap leverthen swung by the spring, the lever locking the oscillating weight in the one direction of rotation of said driven member and releasing the weight in the other direction of rotation of said driven member.

Other objects and features ot' the invention will be apparent as the following description proceeds, reference being had to the accompanying drawings, illustrating by way of examples, two embodiments of my invention, and wherein Fig. l is a plan View ot the parts of the movement which are necessary for an understanding of the invention;

Fig. 2 is a section along the line A-B of Figure l.

erated by said cam in a manner 2,709,332 Patented May 31, 1955 rice Figure 2A is a section along the line C-D--E-B oi Figure 1.

Fig. 3 is a plan view of a detail,

Fig. 4 is a sectoinal view along the line F-G-H of Figure l.

Figure 5 is a plan view at an enlarged scale of a detail.

Figure 6 is a plan view of a portion of a movement in accordance with a modified form of the invention.

Fig. 7 is a section along the line I-K of Fig. 6.

A pinion 2 is rigidly connected with the barrel 1, while a pinion 3 or" the same diameter and number of teeth as pinion 2 is rigidly fixed to the barrel arbor 4. The pinion 2 is permanently in mesh with the drive wheel 5 loosely mounted on a shoulder 6 of the pillar plate 7 while the pinion 3 engages a drive wheel 8 of the same diameter and number of teeth as wheel 5. Wheel 8 coaxial to wheel 5 is in rigid connection with a sun wheel 9 and, together with the latter, revolvably mounted on the sleeve 1li which rotates around a pin 11 lixed to the pillar plate The sun wheel 12 is rigidly fixed to the sleeve 1). Two intermeshing planet wheels 13 having equal diameters and numbers of teeth are revolvably mounted on the drive wheel 5. The one of these planet wheels engages the sun wheel 12 and the other the sun wheel 9. A disk 14 with a cam 15 is rigidly attached to the sleeve 10 constituting the driven member of the differential gear. A pinion 38 is fixed to the outer end of the sleeve 10 and drives a hand l by means of a toothed wheel 16, the hand 17 indicating the development condition or degree of tension of the motor spring (not shown) located in the barrel 1. According as the barrel arbor 4 is driven by the oscillating weight 1S with the aid of means not shown, or the barrel 1 is rotated by the developing motor spring, the differential gear rotates disk 14 with cam 15 either in the anticlockwise or clockwise direction of Fig. l.

A lever 2li is revolt/'ably mounted on a pin 19 of the pillar plate 7 at such a friction resistance that it cannot rotate by itself. A spring 22 is attached on the collar 21 of the lever 2d. The collar 2 is flattened as at 39 (Fig. 3) and the wall of the hole of spring 22 has a corresponding even portion so that the spring 22 cannot turn relatively to the lever 2d. The lever 26 is at the same level with the control cam l5 of disk l-/i so that it can be opdescribed later on. The spring 22- comprises two portions 23 and 2li which, in relieved condition, are practically straight-lined. They are connected with each other by a curved portion 25 which provides for a favorable detormability of the spring 22. The portion 23 of spring 22 traverses with play an opening 2o of the iiattened portion 27 of a pin fixed to the locking or snap lever 2S, this pin permanently coupling the spring 22 with the lever 2S. The latter is pivoted on the pillar plate 7 by means or" the pin 29. Pin 29 carries a stop pin 30 against which abuts the end of spring 2:2 from the one side (Fig. l). Lever 218 is formed with a bend as indicated at 31 and its free end lies at the level of the oscillating weight 1S. This free end has two recesses 32 and 33 and the oscillating weight 18 carries at its ends pins 3d. and 35 respectively. Recess 33 and pin 34, as well as recess 32 and pin 3S form each the halves of two couplings, engaging each other for locking the oscillating weight 13. The snap lever 28 has stop faces 36 and 37 to cooperate with the pin 34 or 35 respectively in order to return the snap lever 2S, which has before been swung by the spring 22 in the anticlockwise direction, in the clockwise direction far enough to allow either the pin 34 to engage the recess 33 or the pin 35 to mesh with the recess 32.

The Shown and described device operates as follows:

With reference to Fig. 1 the snap lever 28 is in locking position and the pin 34 engages the recess 33. Therearcanes fore, the weight 18 cannot oscillate. The motor spring develops and thereby the barrel 1 turns the disk 1liwith cam 15 in the clockwise direction in Fig. l by means of the differential gear. In Fig. 1 the cam 15 already abuts against the lever 2Q and swings the latter in the anticlockwise direction. The spring 22 rests against the stop 3i?, but is not yet deected. On further movement of lever 2i? the spring 22 cannot turn in the anticlockwise direction in Fig. 1, since it butts against stop 3i?. Therefore, it is now being deflected that it is bent towards the right in Fig. l. The play of spring 22 in the opening 26 of the part 27 is sutticient to prevent the deflection from having an undesired inuence on lever 25s so that the recess 33 cannot be moved out of reach of the pin 34. After a certain increase of the deflection of spring 22 owing to the movement of lever 2t? under the a cam 15, the spring 22 slides off the stop 3' and it is tree to relieve. On returning into unstressed condition the spring swings lever 23 suddenly in the clockwise direction of Fig. l until lever 2S strikes against external stop not shown. The recesses 32, 33 and the stop faces 36 and 37 of lever 28 go out the path of the pins and 35 of the oscillating weight l. The weight 18 can now oscillate and wind up the motor spring in the barrel l. While the above phenomena occurred, cam 1S became free to pass by the lever 29 into the right-hand c dotted end position of Fig. l. After lever 28 having struck against the external stop (not shown) the spring 22 has completely stretched itself and thereby slightl returned the lever Ztl in the clockwise direction so that its free end lies again in the path of earn l5. The cam 15 is now on the right of lever 23 and spring 2?. lies at the opposite side of stop 30.

As the oscillating weight 1S winds now up the motor spring, the barrel arbor 4, by the aid of the differential gear, turns the disk 14 back in the anticlockwise direc4 tion of Fig. l. Cam 15 butts against the lever 2t? from the right in Fig. l, swings it in the clockwise direction and presses spring 22 against the stop fill. Therefore, for the time being, spring 22 cannot move lover 28 out of non-locking position in the anticlockwise direction and it is being bent in the opposite direction than before, i. e., towards the left in Fig. l. When a certain deiiection is reached, the spring 22 can slide oil the pin 3@ from right to left in Fig. l whereupon it stretches itself and suddenly throws lever 23 back in the anticlockwise direction until lever 28 rests against an internal stop not shown. Now, lever 23 lies in the path of the pins 3a and 35. According to the momentary position of the oscillating weight 18 on the sudden movement of lever 28, either pin 34 strikes against the face 35 or the pin 35 against the face 37 and slightly returns lever 23 in the clockwise direction against the constraint of spring 22 until pin 3ft or 35 respectively cornes into reach of recess 33 or 32 respectively, whereupon the spring 22 suddenly throws lever 28 back in the anticlockwise direction so that either pin 34 engages recess 35 or pin 35 meshes with recess 32. While these phenomena occurred, cam i5 has passed by the lever 2li. After the lever 28 having struck against the internal stop (not shown), the spring 22 has completely stretched itself and has thereby slightly moved back the lever Ztl in the anticlockwise direction so that its free end lies again in the path of the cam 15. The described cycle is now repeated.

Since cam 15 positively driven by the differential gear operates lever 2S by means of spring 22 always after the same prescribed value of the winding or development rotation of the motor spring, winding up and developing of the latter always to the same limit is guaranteed indethis fact results in an increase of life of delicate parts.

Figs. 6 and 7 show another shape and position of the snap lever 23a. While in the example of Figs. l to 4 the recesses 32 and 33 are provided on that end of the twoarrned lever 2S, which is turned away from the disk 14, the coupling half of the one-armed lever 2da of Figs. 6 and 7 is in the shape of a pin 4t) mounted on that end of lever which is turned towards the disk 14. According to the momentary position of the oscillating weight i8, the other coupling half is constituted by one of several recesses 41 distributed along the inner edge of the weight 18. The fact of providing several recesses 41 oiiers the advantage of the latter, after arrival of lever 23a in locking position and at certain momentary positions of the oscillating weight, being stopped quicker than in the first embodiment where coupling halves are only provided on the ends of the oscillating weight.

VWhile have shown and described two examples of my novel device, I do not wish to unnecessarily limit the scope of my invention, but reserve the right to make such moditications and rearrangements of the several parts that may come within the purview of the accompanying claims.

What l claim is:

l. An overwind preventer for a timepiece comprising oscillating weight winding mechanism including a barrel and a barrel arbor, a diterential gear operatively connected between the barrel and the barrel arbor, locking means for the oscillating weight, a spring, a stop for the spring, operating means connected with the diierential ear to move the spring past the stop, and a snap action locking lever swung by the spring locking the oscillating weight in the one direction of the diierential gear and unlocking the oscillating weight in the opposite direction of the differental gear.

2. An overwind preventer tor a timepiece comprising oscillating weight winding mechanism including a barrel and a barrel arbor, a differential gear operatively connected between the barrel and the barrel arbor, locking means for the oscillating weight, a spring, operating means connected with the ditterential gear to move the spring, a snap action locking lever for the oscillating weight, the spring permanently coupled with the snap action locking lever, and a stop positioned within the axis of rotation of the locking lever, the spring adapted to contact the stop and bend to thereby pass the stop whereby the locking lever is moved to and away from the oscillating weight depending upon the direction of rotation of the diferential gear. Y

References ited in the le of this patent UNITED STATES PATENTS 332,023 Von Der Heydt Dec. 8, 1885 FOREIGN PATENTS 75,789 Switzerland Sept. 17, 1917 155,515 Switzerland Sept. 16, 1932 

